In-Cahoots FAIL

Two papers in the current issue of American Journal of Physical Anthropology on Homo floresiensis, our dear friend the supposed hobbit. I can’t help but present one sentence from each paper, out of context:

“Insofar as we can tell, LB1, who lived to be a mature adult female, did not suffer from LS [Laron Syndrome] and was not pathological.” (Falk et al. 2009, p. 61, my emphasis)

“As asymmetric craniofacial deformities are not typically seen in a skull with intentional artificial deformation, the aforementioned asymmetric deformities [of LB1] are likely to have been caused by some pathological or abnormal condition.” (Kaifu et al. 2009, p. 180, my emphasis)

Just a little funny that two independent papers supporting the new-species status of H. floresiensisseem to say opposite things. To be fair, when Falk et al. state that LB1 “was not pathological,” they mean that there is no convincing argument that a pathology or disease could cause a modern human skull to look like that of LB1. And Kaifu et al. are referring to the condition of “posterior deformational plagiocephaly,” a not uncommon and presumably non-debilitating phenomenon in recent and historic modern humans, as a result of a persistent application of non-uniform pressure to a child’s developing cranium (like consistently sleeping with one’s head in a certain position). But the ambiguity of words like “pathology” allow the two sentences above to be juxtaposed to make it look like each paper makes contrary arguments.

Nevertheless, the papers do underscore a problem with fossils selected to be the holotypes of new species. Clearly, there is something pathological about LB1, but the extent to which a given pathology undermines the species-status of H. floresiensis is debated. And selection of pathological specimens as holotypes has occurred before: the holotype of Ardipithecus kadabba, one of the earliest and more questionable early hominins, has a first molar socket which “is extensively altered by pathology” (Haile-Selassie et al. 2009, p. 164). And a lot of species, and even genera, have been erected around subadult holotypes, too, which can be problematic.

This is just one of myriad issues we get to deal with in human paleontology.

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3 thoughts on “In-Cahoots FAIL”

I'm not sure if there is surely something pathological about LB1 but I do think that using a holotype to represent the whole species is rather problematic. Though it's something we need to make due until another fossil of the same species is found.

Well, it's standard paleontological practice to designate a single fossil as the type specimen, to which other fossils can be compared to see if they belong to the same species. And you're right, this is problematic because there's nothing inherent in a holotype that can give an idea of intraspecific variation.I think there is something odd about LB1, but I'm not convinced that pathology can explain its early-Homo-like appearance. And as you point out, we really don't have other cranial materials for this 'species' to get an idea of normal variation in that lineage. There's an additional mandible, which is also very small. But without other fossils to compare it to we cannot say to what extent LB1 is likely aberrant or not, asymmetrical or what.

Just saw this site for the first time today so am not sure what "In-Cahoots FAIL" means.My compliments to Zacharoo for noticing the contradictions in remarks by Kaifu and Falk. I will not try to lead you in any specific directions, but will note that there are a LOT more howlers of all sorts in the responses by Kaifu, Falk and McNulty.Anyone who wishes to understand what is going on with the promotion of "Homo floresiensis" would do well to read "Plastic Fantastic" by Eugenie Samuel Reich.Here's hoping that your experience as Michigan Anthropology grad students will prove as rewarding as mine were a LONG time ago (1964 – 1971, joint degrees with Human Genetics).Best,Bob Eckhardt